7-[3-(propylamino)-2-hydroxypropoxy]flavone and its acid addition salts are useful as antihypertensive agents as described, for example, in U.S. Pat. No. 4,495,198. In this patent, the specification of which is herein incorporated by reference, the subject compound is shown to have been prepared in about 48% yield from the reaction of 7-(2,3-epoxypropoxy)flavone with n-propylamine. A major by-product of this reaction, and thus a cause of the moderate yields, is the formation of the corresponding beta-aminochalcone due to opening of the pyrone ring. Chalcone formation is well-known and has been reported by researchers such as Zagorevskii et al, Chem. of Heterocyclic Compounds, 7(6), 675 (1971); Baker et al, J. Chem. Soc., 2142 (1949); and Jerzmanowska et al, Monatshefte fuer Chem., 98(4), 1395 (1967).